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https://repository.uinjkt.ac.id/dspace/bitstream/123456789/38256/9/BAB%208%20Kardiovaskular.pdf
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http://eprints.umm.ac.id/41106/3/jiptummpp-gdl-rikaoktani-47110-3-bab2.pdf
https://skillslab.fk.uns.ac.id/wp-content/uploads/2019/02/smt-4-Interpretasi-EKG.pdf
https://inaheart.org/wp-content/uploads/2021/07/Buku-Appropriateness_drafttt-final_Review-Kedua.pdf